Safety inspection regarding open wheel shooters?

[HayWire1569]

After reading through threads here on Chief Delphi, our team (1569) is concerned about our open wheel shooter. What have been the difficulties regarding open wheel shooters, and which part of the wheels need to be covered to be considered safe?

I will also upload a photo of it tomorrow, or check out the video of our robot on YouTube.

[pfreivald]

Originally Posted by HayWire1569

After reading through threads here on Chief Delphi, our team (1569) is concerned about our open wheel shooter. What have been the difficulties regarding open wheel shooters, and which part of the wheels need to be covered to be considered safe?

We had no issues with our open-wheeled shooter at FLR... But our wheels are solid rubber 6" Colsons. I can't speak for others with different wheels.

[Jaxom]

Originally Posted by HayWire1569

After reading through threads here on Chief Delphi, our team (1569) is concerned about our open wheel shooter. What have been the difficulties regarding open wheel shooters, and which part of the wheels need to be covered to be considered safe?

I covered this from my Hub City experience in Al's annual inspection thread; see http://www.chiefdelphi.com/forums/sh...8&postcount=30 and http://www.chiefdelphi.com/forums/sh...5&postcount=32

Bottom line -- wheels got covered on every robot.

[Jeff Pahl]

Like many things, the answer is "it depends".

I'm sure I'll get to look at lots of unshielded shooter wheels in the next few days. My feeling on the subject is that any moving parts that extend outside of the mechanism such that they could catch clothing, hair, fingers, etc in the pits, or that could make contact with another robot or the field while on the field, will need to be enclosed. Obviously, you can't cover the part of the wheel where it makes contact with the disk, which hopefully is within the mechanism and is reasonably enclosed.

Again, "it depends" on the exact implementation of the mechanism in question and the opinion of the LRI at any particular event. I fully anticipate this being the "headache issue of the year" at Championship, and my advice would be to err on the side of caution and safety.

[Kevin Sevcik]

We're getting materials together to put a quick shroud around our small wheeled shooter at Lone Star. Some ABS sheet and a plastic bending heater strip. I'm assured it'll take all of half an hour to cut, bend, and mount the plastic.

[Gregor]

No open wheeled shooters had to be covered at FLR (us included), from what I observed.

[HayWire1569]

Originally Posted by Jaxom

I covered this from my Hub City experience in Al's annual inspection thread; see http://www.chiefdelphi.com/forums/sh...8&postcount=30 and http://www.chiefdelphi.com/forums/sh...5&postcount=32

Bottom line -- wheels got covered on every robot.

Thank you, and these are the exact threads an posts I was referring to. We are planning to build a shield, just to be cautious, and adjust it as needed when we get to regionals. My final question, do the front of the wheels need to be covered, or just the side and tops?

[dtengineering]

It would be great if FIRST would provide some guidance on this issue so that there is a uniform standard (as much as possible) at all competitions.

I will be inspecting in Seattle and Calgary, and while the Lead Inspector is the one who gets to make the final call, I'll certainly be looking for mechanisms to ensure that fingers, hair or other unexpected objects are not likely to come into contact with the wheel. Based on my experience in previous years, I expect to be able to reach agreement with most teams on what is reasonable. No one wants an unsafe robot.

One thing that I really liked was the plan for a team to bring ABS and a strip bender... perhaps teams that have the resources will set up a "shielding shop" to help less well-resourced teams improve their robot. Even 1/16" polycarb is likely enough to keep fingers out, and it can be cut and bent relatively easily if you've got access to the material and tools.

Jason

[Jaxom]

Originally Posted by HayWire1569

do the front of the wheels need to be covered, or just the side and tops?

That depended on the existing design. There were some bots that only had a tiny bit of wheel uncovered in the front; we left those alone. Others had huge percentages of a wheel exposed; those were covered. Unfortunately, it's an "it depends" situation.

This wasn't just an "in case the wheel starts disintegrating" thing. One team had a wheel from a baseball pitching machine. It was factory-balanced and rated for some unearthly number of rpms. It got a cover.

One of the mentors for a team I was inspecting verbalized a great thought test for this. Ask yourself: would you be comfortable with this spinning at full speed with you and the bot in a phone booth? Both he and I are old enough to remember such structures; others may need to use Wikipedia.

[Tom Line]

Originally Posted by dtengineering

It would be great if FIRST would provide some guidance on this issue so that there is a uniform standard (as much as possible) at all competitions.

Jason

I am going to agree with this whole-heartedly. Last year, there were very very few guards that I saw around any shooter wheels. We ran ours at 4,000 rpm, not much different that what we're running this year.

Yet this year (per the first post), some inspectors are enforcing that they must be guarded.

I understand full well the difficulty FIRST faces in attempting to write rules. However, in this case, we have polar opposites going on at regional competitions. That's confusing, and for a robot who is right on the edge weight wise can be extremely distressing. Please FIRST, put out a rules update stating that the outside of all shooter wheels must be covered. Bite the bullet and let everyone know now so they can plan.

[Jon Stratis]

At my regionals, my default position will be to require covers over all shooter wheels. It is up to the team to convince me that the danger of caught fingers/hair/clothing is acceptable, and that the wheel won't suffer from sudden and catastrophic failure (for example, the rubber tire on most of these pneumatic wheels could easily stretch and come off at an unexpected angle during a match).

The best route to convince me will be a datasheet from the manufacturer that specifically lists an operating range that includes the speed your running the wheel at. Good luck finding that... even AndyMark's pneumatic wheel states "The design intent is to be contacting the ground, being driven by a gearbox at a maximum speed of approximately 500 rpm".

Given that statement, running the wheel at 10 times its intended speed, with variable and sudden loading on it from shooting, I WILL require appropriate safeguards placed around the wheel.

[Wayne Doenges]

Originally Posted by Tom Line

I understand full well the difficulty FIRST faces in attempting to write rules. However, in this case, we have polar opposites going on at regional competitions. That's confusing, and for a robot who is right on the edge weight wise can be extremely distressing. Please FIRST, put out a rules update stating that the outside of all shooter wheels must be covered. Bite the bullet and let everyone know now so they can plan.

This will probably tick off several people but I have two words concerning guarding: Common Sense
You have a wheel turning at 5000+ rpm in the pit and it self destructs or someone accidentally drops a tool in it or someone gets too close. Would you want to call someone's parents and explain how their child was injured because you didn't guard the wheel?
If this made someone angry, I apologize.
* puts on flame suit *

[engunneer]

Originally Posted by Wayne Doenges

This will probably tick off several people but I have two words concerning guarding: Common Sense
You have a wheel turning at 5000+ rpm in the pit and it self destructs or someone accidentally drops a tool in it or someone gets too close. Would you want to call someone's parents and explain how their child was injured because you didn't guard the wheel?
If this made someone angry, I apologize.
* puts on flame suit *

Agree - this falls into two basic life rules -
1. "Consider the headline" if something goes wrong.
2. Don't stand in the plane of destruction.

[FrankJ]

Trouble is wheel guarding is anything apparently anything but "common sense" True guarding would prevent any chance of being able to touch a wheel while it is moving. Sort of like an OSHA approved coupling guard. The guarding you need for protecting the wheel is a lot different than what you will need for when the wheel shatters.

Common sense would tell you to keep the pit area clear of any non essential people especially visitors. Guarding in the pits should include any mechanism capable of sudden movement, pinch points, etc. I think this would impact the overall goal of First if we went fully down this road.

I am not really arguing the need to properly guard rotating components. I do think there needs to be more published guidance from First & not left up the event's lead inspectors discretion.

PS I think this needs intelligent discussion without the need for flame suits.

[FrankJ]

Here is a photo from Frank's blog of some "great robots" at BAE tournament practice day. Presumably they passed inspection.